GroupTheory`
GroupTheory`

GTPhBandsObjects

GTPhBandsObjects[objects,background permittivity,reciprocal basis, cutoff, k-points, number of bands]

calculates number of bands of a photonic band structure at k-points. The system is defined by objects
and the given background permittivity. The reciprocal basis and cutoff are used to construct a cluster of reciprocal lattice vector.

Details and Options

  • In GTPhMaster, GTPhMasterObjects and GTPhMasterPixel the eigenvalue problem of the master equation is constructed in a general form, the corresponding matrix can be stored as a function of . The matrix can be used to calculate eigenvalues for bandstructures or densities of states. In the three-dimensional case the analytic expressions stored in the matrix becomes complex and the numerical evaluation for a large number of reciprocal lattice vectors becomes very time consuming. In GTPhBandsObjects the matrix is constructed for each k-point numerically. This speeds up three-dimensional considerably.
  • The list objects contains the description of the geometrical objects in the unit cell. The description of an objects is given by a list:
  • objects = {{identifier, permittivity, geometry, shift},...}
  • The identifier defines the name of the object. Furthermore the permittivity inside the object is defined. The list geometry defines filling factor, size and shape of the object. The object can be shifted with respect to the origin by the vector shift.
  • The following option can be given:
  • GODCMethod "Direct"Method to calculate the matrix
    GODecimals 4Controls the number of fractional digits in tables
    GOPhPol "Automatic"Specifies the polarization.
    GOPlotBands TrueControls calculation of energy bands in the Brillouin zone.
    GOStore 0Controls output of bands and eigenvalues to files.
    GOVerbose TrueControls the output of additional information.
  • See: W. Hergert, M. Geilhufe, Group Theory in Solid State Physics and Photonics. Problem Solving with Mathematica, chapter 10
  • K. M. Ho, C. T. Chan, C. M. Soukulis, Existence of a Photonic Gap in Periodic Dielectric structures. Phys. Rev. Lett. 65, 3152 (1990).

Examples

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Basic Examples  (1)

First load the package:

A circular rod in a quadratic unit cell is defined according to the rules in GTPhDCObjects.

The path in the Brillouin zone for the plot of the photonic band structure is calculated.

The photonic bands for TE polarization are calculated and plotted.

Options  (6)

GODCMethod  (1)

Using Ho method

Compare the calculations witht he different methods. Differences are mainly due to the low number of plane waves used in the calculations.

GODecimals  (1)

6 fractional digits are used in the table. The standard is 4.

GOPhPol  (1)

The structure is two-dimensional, i.e. the polarization has to be TE or TM.

H and E polarization will be changed automatically to TE and TM.

GOPlotBands  (1)

It is possible to generate data for a DOS calculation

More k-points will result of course in a better DOS.

GOStore  (1)

The results can be stored to a file and then used, to plot the band structure or to calculate the density of states.

GOVerbose  (1)

Additional Information can be switched off.